Effects of nimodipine on regional blood flow in heart and brain during cardiopulmonary resuscitation in pigs.

The effect of nimodipine on organ blood flow during cardiopulmonary resuscitation (CPR) was studied in 26 anesthetized pigs. After 5 min of ventricular fibrillation circulatory arrest and 5 min of external CPR, all animals received 50 micrograms/kg of epinephrine and either nimodipine (10 micrograms/kg, followed by 1 microgram.kg-1.min-1 until termination of the experiment) or placebo. Organ blood flow was measured using radioactive-labeled microspheres. The rate of resuscitability in nimodipine-treated pigs (11 of 12) was significantly higher (P < 0.05) than in placebo-treated animals (7 of 14). In pigs receiving epinephrine and nimodipine, left ventricular blood flow after restoration of spontaneous circulation (ROSC) was approximately twice as high as in pigs receiving epinephrine and placebo (P < 0.01). In nimodipine-treated pigs, total cerebral blood flow 10 min after ROSC was significantly higher than baseline values (P < 0.01) and in hypophysis, cerebellum, and medulla the blood flows were significantly higher than in placebo-treated pigs (P < 0.05). We conclude that, in our pig model, high doses of nimodipine given during CPR caused significant enhancements in left ventricular blood flow and significantly improved the rate of resuscitation.